Absolute Neutron Emission Measurement in Burning Plasma Experiments

The absolute measurement of neutron emission rate from the whole plasma is a very important diagnostics as a fusion power monitor in fusion experimental devices with D‐T or D‐T operations. Here measurement techniques of time‐resolved and time‐integrated absolute neutron emission on the present tokamaks and ITER are reviewed. In the present tokamaks, fission chamber installed outside the vacuum vessel are very popular in the absolute neutron emission rate measurement. As well as conventional neutron monitors installed outside the vacuum vessel, in‐vessel neutron monitors using micro fission chamber are proposed for the absolute neutron emission rate measurement in ITER. The neutron activation system provides time‐integrated measurements of the total neutron yield with high accuracy by using well known neutron reaction cross sections, which is useful to maintain a robust measure of fusion energy production with stability and wide dynamic range. The calibration of the relation between the neutron emission ra...